Core signalling device



May 7, 1957, w. M. oRr-:ILLY ErAL COREYSIGNALLING DEvxcE Filed Jan. 17. 1955 IN VEN TOR Marl/'n E. True,

Wal/ace M. OReII/y,

Arran/vn United States Patent O M' CORE SIGNALLING DEVICE Wallace M. OReilly and Martin E. True, Houston, Tex., assignors, by mesne assignments, to Esso Research and Engineering Company, Elizabeth, N. J., a corporation of Delaware Application January 17, 1955, Serial No. 482,023

6 Claims. (Cl. 2551.4)

The present invention is directed to a device for indicating the taking of a core in a well bore. More particularly, the invention is directed to a core signalling device adapted to be arranged in a core barrel positioned in a drill string. In its more specic aspects, the invention is concerned with a device which signals or detects the taking of a core at the well head.

The present invention may be briefly described as a core signalling device adapted to be arranged in a wire line retrievable core barrel adapted toibe arranged in a drill string. The device comprises means carried on the exterior thereof for diverting pumped drilling uid through the device. A rotatable valve means is arranged in the device in the path of llow of the diverted drilling lluid. Means are connected to the rotatable valve means actuatable by entry of the core in the core barrel which rotates the valve means and decreases the flow of drilling iluid through the device whereby increase in pressure of the pumped drilling lluid signals entry of the core in the core barrel.

The device of the present invention comprises a core cutter, a core barrel, and a core catcher in the core barrel. Initially arranged adjacent the core catcher is a core follower which is attached, by a longitudinally extending means such as a iluted or helical driving rod, to a rotatable valve means arranged in operative relationship to a fixed valve means. The rotatable valve means is an oritce plate having ports adpted to be placed into alignment with ports in the xed valve means.

The device of the present invention is provided with a packing means on its exterior surface whereby drilling lluid is diverted through the device and through the valve means such that rotation of the rotatable valve means by the core entering the device causes flow of drilling fluid to be interrupted which results in an increase of pressure of the pumped drilling lluid which indicates when a core is being taken.

The present invention will be further illustrated by reference to the drawing in which:

Fig. l is an elevational view partly in section of the device of the present invention shown in coring position in a conventional well bore;

Fig. 2 is a front sectional view of the upper portion of the device shown in Fig. 1;

Fig. 3 is a front sectional view of the lower portion of the device shown in Fig. 2;

Fig. 4 is a plan view of the core follower and driving rod o f Fig. 2; l

Fig. 5 is a plan View of the rotatable vorifice plate of Fig. 2;

Fig. 6 is a plan view of the lixed orifice plate of Fig. 2;

Fig. 7 is a plan view of the drive collar of Fig. 2; and

Fig. 8 is a detail of the latching dog of Fig. 1.

Referring now to the drawing in which identical numerals will be employed to designate identical parts, numeral 11 designatesV a core barrel provided with a core cutter 12 and adapted with a fishing neck arrangement 13 to permit its use with a wire line. It may be 2,791,398 `iiaterrted May 7, 1957 gravitated into position in the lowermost portion of a drill string 14 extending to the earths surface and connected to a source of drilling fluid being pumped under pressure. The lower end of the drill string 14 has a core bit 14a attached thereto through which the core cutter 12 projects.

The core barrel 11 may be provided with a core catcher 15 comprised of spring members 16 which serve to hold the core, when taken, in the core barrel.

Arranged immediately above the core catcher 15 in the passageway 17 of the core barrel 11 is a core follower 13 which is connected to a driving rod 19.

The drive rod 19 is keyed by a guide key 20 which engages with a keyway 21 against rotational movement in the passageway 17. The upper portion of the driving rod 19 is provided on its exterior surface with a fluted, twisted, or helical surface 22 which matingly engages with a surface 23a of a drive collar 23 which is threadably connected by mating threads 24 with an adapter cylinder 25.

The upper end 26 of the driving rod 19 is arranged in the passageway 2327 defined by surface 23a of the drive collar 23 such that engagement of the surface 22 with the surface 23a causes rotation of the adapter cylinder 25.

The passageway or chamber 17 is provided with a plurality of relief valves 27 comprised of seating members 28 threadably connected by mating threads 29 into the core barrel 11 and spherical valve members 31B biased onto the seats 31 by helical coil springs 32. The spherical seating members 30 serve to close olf the passageways 33 and to open same for discharge through lateral passageways 34 on movement of the guide key 20 and core follower 18 upward in the chamber or passageway 17.

The adapter cylinder 25 is rotationally mounted on ball bearings 35 arranged in bearing retaining rings 36. The upper end of the adapter cylinder 25 is sealed against the inner wall 37 of the core barrel 11 by means of sealing members 38 and 39.

Attached to the upper end of the adapter cylinder '2S is a cage member 42 provided with a plurality of ports 43 communicating through lateral passageways 44 with the interior entry chamber 45 of the device and with the annulus A between the device and the drill string 14.

Attached to the upper end 46 of the cage 052 by mating threads 47 is a rotatable valve orifice plate 4S provided with a passageway 49 and sized orifices Si) and 51. The rotatable valve plate 4S is in operative relationship with a xed valve plate 52 which is threadably connected to the core barrel 11 by mating threads 53. The first valve plate 52 is provided with a passageway 54a of the same size as passageway 49 and with an orifice slot 54.

The core barrel 11 is provided with lateral passageways 55 for diversion of drilling fluid from the annulus A through the valve means. The drilling lluid is diverted through the valve means comprised of plates 43 and 52 by means of a packer such as an upwardly facing cup packer 56.

The core barrel of the present invention may be constructed of a lower section 57 connected to an intermediate section 58 by mating threads 59 which, in turn, is connected to an upper section 60 by a connecting assembly tla using mating threads 61 and to a top packer section 62 by mating threads 63; it is possible to construct the device integrally. However, it is preferred to construct the device in sections as has been indicated for convenience of assembly and/or maintenance.

Attached to the upper end of the core barrel 11 by mating threads 8 is a latching and retrieving assembly 9 provided with a iishing neck 13 and latching dog 10. rl`he core barrel 11 is retained against upward movement in drill string 14 by means of the latching dog 10 engaging with a recess '7 in the drill string. The latching dog 1l) 3 is biased outwardly by a biasing spring a and the dog 10 rides against the interior wall of the drill string 14 until the recess 7 is reached at which time it is forced outwardly into the recess to engage therewith.

The device of the present invention operates as follows:

The core barrel l is lowered into the drill string 14 until the dog 1li locks 'the core barrel l1 in the recess 7. Thereafter, as the drill string 14% and the core barrel 11 are rotated, the core, not shown, enters the core barrel through the core cutter as the core barrel 11 moves downwardly over the drive rod 19, the core follower 13 and the core. This causes drive rod 19 to move through the passageway 23b of drive collar 23. The 'fluted or helical surfaces 22 engage with surface 23a and cause the drive collar 23 and the adapter cylinder 2S to rotate which, in turn, rotates the cage 4Z. in the meanwhile drilling fluid which is being pumped down the drill string 14 is diverted through passageways 55 by closing off the annulus A by means of pressure exerted against the cup packer 56. The drilling fluid will normally pass through the orifices 49 and 54a, the orifices 50, 51 and 54 in plates 4S and 52. However, rotation of the adapter cylinder and the plate 4S causes a fluctuation in the pressure of the drilling fluid by virtue of alternate placing of the orifies Sil and S1 in alignment with the orifice slot 54. The reduction of free passage of the drilling fluid through the ports 55 and 43 and thence to port 44 to annulus A causes a pressure signal to be transmitted to the well head, not shown. This may be observed visually on the mud pump gauge or may be recorded automatically.

By virtue of the pressure signal, it is possible to tell when a core is entering the core barrel since there is a series of significant changes in pressure only when the core is entering the core barrel. Since entry of the core in the core barrel causes rotation of the plate 48, this signals the core entry and core cutting. Thus the pressure at the earths surface may be automatically recorded as a plot of mud pressure versus depth or observations of pressure variations will indicate the depth at which cores are or have been taken and when cores are satisfactorily entering the core barrel. For example, the present invention will indicate the taking of cores satisfactorily in increments as small as l foot. After the core has been taken the core bar-rel 11 may be retrieved by engaging a wire line fishing tool with the fishing neck 13 and lan upward pull releases dog 10 from the recess 7 allowing the apparatus to be retrieved from the well.

The present invention is quite useful as -a core indexing or core signalling device in that it reflects the depth from which cores are taken within predetermined intervals and permits prolonged single coring trips since the coring assembly need not be pulled until it is filled with core samples.

Besides indicating the depth at which cores are taken by pressure fluctuations and besides signalling positively when cores are entering the core barrel, the present invention is quite advantageous in that the core does not come into contact with drilling fluid or drilling mud circulated through the device. Therefore, the ypresent invention is quite advantageous.

The fluctuation in drilling vfluid pressures possible in the use of the present invention may be employed to determine the amount and/or length of cores recovered from the various intervals penetrated and precise corre lation may be effected with well depth in subsequent core analysis.

The present invention indicates when the core barrel is filled and obviates premature round trips to recover incomplete cores. By round trip is meant going into the hole with the drill vstring or wire line coring assembly and coming out of the hole with Ithe 'wire `line coring assembly or drill string to remove a drill bit and/'or a c'ore barrel.

The nature and objects of the present invention having been completely described and illustrated, what we wish to claim as new and useful and to secure by Letters Patent is:

l. A core signalling device adapted to be arranged in a retrievable core barrel in a drill string through which drilling fluid is being pumped, said retrievable core barrel being provided with a chamber having an inlet and an outlet providing a path of flow for drilling fluid through the chamber which comprises, packing means carried by said core barrel on its exterior surface for diverting said pumped drilling fluid through said chamber, -valve means comprising a fixed orifice plate and a rotatable orifice plate arranged in said chamber in the path of flow of said diverted drilling fluid, and core follower means opcratively connected to said rotatable orifice plate, said core follower means being actuated by the core entering said core barrel and said core follower means rotating said rotatable orifice plate and thereby decreasing flow of drilling fluid through said chamber whereby an increase in pressure of the pumped drilling fluid signals entry of the core into the core barrel.

2. A core signalling device adapted to be arranged in a retrievable core barrel in a drill string through which drilling fluid is being pumped, which comprises, said retrievable core barrel provided with a chamber having an inlet and outlet providing a path of flow for drilling fluid through the chamber, an upwardly facing cup packer carried by said core barrel on its exterior surface for diverting said pumped drilling fluid through said chamber, valve means compris-ing a fixed orifice plate and a rotatable orifice plate arranged in said chamber in the path of flow of said diver-ted Ydrilling fluid, an elongated member connected to said rotatable orifice plate for rotating said rotatable orifice plate, core follower means connected to said elongated member, said core follower means 'being forced upwardly by the core entering said core barrel and thereby rotating said elongated member and said rotatable orifice plate and decreasing flow of drilling fluid through said 4chamber whereby an increase in pressure of the pumped drilling fluid signals entry of the core in the core barrel.

3. A device in accordance with claim 2 in which the elongated member is provided with a helical surface matingjly connectedto said rotatable orifice plate for rotating said rotatable orifice plate.

4. A core signalling device which comprises a retrievable core barrel provided with a core cutter and having a ychamber isolated from the `core barrel, said chamber having an .inlet kand -an outlet providing a path of flow for drilling flu-id through thc chamber., said device being adapted to Ybe arranged ina drill string through'which drilling .fluid is being pumped, means carried by said core barrel for diverting pumped drilling fluid .through said chamber, valve means comprising a fixed orifice lplate and a rotatable orifice plate arranged in said chamber in the ,path of flow of said diverted drilling fluid, Aand core follower means operatively connected Ito said rotatable orifice valve plate, said core follower means being yactuated by the core `entering said core barrel 4and said core follower means rotating said rotatable orifice plate and thereby decreasing flow of-drilling -fluid .through 'said chamber whereby an increase `in pressure .of the `pumped drilling fluid signals entry ofthe core -into the core barrel.

5. A core signalling device which comprises, .a retrievable core barrel provided with a core lcutter and having a chamber isolated from the core barrel, said chamber -having @aninlet andan-outlet providing a path ofrflow for drilling fluid through fthe chamber, said device being adapted to be arranged in a ldrill string through which drilling lfluid fis being pumped, an upwardly facing cup packer carried by ysaid core -barrelonits exterior surface for .diverting Vpumped .drilling fluid throughsaid chamber, valve -means comprisinga fixed orifice lplate and a rotatable orifice plate arranged =in saidchamber in the lpath of flow of said diverted drilling fluid, `an elongated member connected to said rotatable orifice plate for rotating said rotatable orifice plate, core follower means connected to said elongated member, said core follower means being actuated by the core entering said core barrel and thereby rotating said elongated member and rotatable orifice plate and thereby decreasing ow of drilling fluid through said core barrel whereby an increase in pressure of the pumped drilling uid signals entry of the core into the core barrel.

6. A device in accordance with claim 5 vin which the 6 elongated member is provided with a helical surface matingly connected to said rotatable orifice plate for rotating said rotatable orifice plate.

References Cited in the le of this patent UNITED STATES PATENTS Re. 21,951 Salnikov Nov. 18, 1941 1,839,417 Scott Jan. 5, 1932 2,503,561 Pickard Apr. 11, 1950 2,652,232 Holland Sept. 15, 1953 

